ipv6 fib: Make rt6_info{} more cache-line aware.

The head element of rt6_info{} is dst_entry{}, and
IPv6 specific elements follow.

Because elements at the end of dst_entry{} are frequently
updated, it is not good to put frequently-used static
elements, such as rt6i_idev, rt6i_dst or rt6i_flags in the
same cache line.

On the other hand, fib6_table, rt6i_node or rt6i_gateway are
rarely used, so it is okay to stay in the same cache line.

Let's rearrange rt6_info{}.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
YOSHIFUJI Hideaki / 吉藤英明 2010-03-31 22:24:22 +00:00 committed by David S. Miller
parent 152102c7f2
commit bd2c77a0a7
1 changed files with 16 additions and 13 deletions

View File

@ -88,34 +88,37 @@ struct rt6_info {
struct dst_entry dst;
} u;
struct inet6_dev *rt6i_idev;
#define rt6i_dev u.dst.dev
#define rt6i_nexthop u.dst.neighbour
#define rt6i_expires u.dst.expires
/*
* Tail elements of dst_entry (__refcnt etc.)
* and these elements (rarely used in hot path) are in
* the same cache line.
*/
struct fib6_table *rt6i_table;
struct fib6_node *rt6i_node;
struct in6_addr rt6i_gateway;
u32 rt6i_flags;
u32 rt6i_metric;
atomic_t rt6i_ref;
/* more non-fragment space at head required */
unsigned short rt6i_nfheader_len;
/* These are in a separate cache line. */
struct rt6key rt6i_dst ____cacheline_aligned_in_smp;
u32 rt6i_flags;
struct rt6key rt6i_src;
u32 rt6i_metric;
u8 rt6i_protocol;
struct fib6_table *rt6i_table;
struct rt6key rt6i_dst;
struct inet6_dev *rt6i_idev;
#ifdef CONFIG_XFRM
u32 rt6i_flow_cache_genid;
#endif
/* more non-fragment space at head required */
unsigned short rt6i_nfheader_len;
struct rt6key rt6i_src;
u8 rt6i_protocol;
};
static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)